Reaction #45307

Reaction equation

N2

lithium acetylide

NaI

10-chloro-1,1-diethoxydecane

→

12,12-diethoxydodec-1-yne

Yield 93.0%

Solvents

DMSO

Conditions

Workup

1. 1
   Temperaturewhile maintaining
2. 2
   Otherreaction temperature around 30° C.
3. 3
   WashThe addition funnel was rinsed with DMSO (15 ml, anhydrous, Su: Acros)
4. 4
   OtherThe solution was monitored by GC for compound 3 consumption (compound 3<2.0 Area % by GC)
5. 5
   workup.ADDITIONH2O (200 ml) were charged into the reaction mixture
6. 6
   Otherto quench
7. 7
   Otherthe reaction
8. 8
   ExtractionThe aqueous layer was extracted with heptane (2×200 ml)
9. 9
   FiltrationThe organic layer was filtered through a plug of Celite® 521 (15 g, Su: Sigma-Aldrich) one by one
10. 10
    Otherafter phase separation
11. 11
    WashThe combined filtrate was washed with a solution of H2O (100 ml) and brine (50 ml)
12. 12
    OtherThe water in this organic solution was removed by azeotropic distillation under normal conditions by means
13. 13
    workup.ADDITIONof adding
14. 14
    Otherremoving heptane (repeat if necessary until KF=˜0.2%)
15. 15
    ConcentrationThe resultant solution was concentrated under reduced pressure (pot temperature ˜35° C.)

Procedure

To a dark solution of lithium acetylide, ethylenediamine complex (13.8 g, 134.90 mMol, (90%) Su: Aldrich) and NaI (0.78 g, 5.19 mMol, (99+%), Su: Acros) in DMSO (100 ml anhydrous (99.7%) Su: Acros) was charged 10-chloro-1,1-diethoxydecane 3 (27.48 g, 103.77 mMol Su: from step B) while maintaining reaction temperature around 30° C., under a blanket of N2. The addition funnel was rinsed with DMSO (15 ml, anhydrous, Su: Acros). The solution was monitored by GC for compound 3 consumption (compound 3<2.0 Area % by GC). After 4 hr stirring at 30° C., H2O (200 ml) were charged into the reaction mixture to quench the reaction. The aqueous layer was extracted with heptane (2×200 ml). The organic layer was filtered through a plug of Celite® 521 (15 g, Su: Sigma-Aldrich) one by one after phase separation. The combined filtrate was washed with a solution of H2O (100 ml) and brine (50 ml). The water in this organic solution was removed by azeotropic distillation under normal conditions by means of adding and removing heptane (repeat if necessary until KF=˜0.2%). The resultant solution was concentrated under reduced pressure (pot temperature ˜35° C.) to give 24.6 g of 12,12-diethoxydodec-1-yne 4 as an amber liquid (93% yield over steps A thru C, after C). This material was used without further purification. GC: column SP, Rt: 12.2 for 10-chloro-1,1-diethoxydecane 3, and Rt: 11.1 min for 12,12-diethoxydodec-1-yne 4 (<5 Area %). 1H NMR (CDCl3, 400 MHz): δ 4.48 (t, J=5.60, 1H), 3.6 (m, J=7.07 Hz, 2H), 3.5 (m, J=7.07 Hz, 2H), 2.18 (dt, J=7.10, 2.80 Hz, 2H), 1.94 (t, J=2.60 Hz, 1H), 1.6 (m, 2H), 1.52 (qn, J=7.2 Hz, 2H), 1.4 (m, 2H), 1.29 (br s, 10H), 1.20 (t, J=7.00 Hz, 6H).

Source